Welsh biotech company Genesis Biosciences has developed a new additive to help bolster the anaerobic digestion (AD) system.
The Cardiff-based company identified a novel mineral carrier with the correct parameters to bolster the most sensitive microbial components of the AD system and, through extensive laboratory genomic screening, it was found that if paired with non-pathogenic and naturally occurring Bacillus microorganisms, it was capable of anaerobic growth, as well as enhanced sludge and organic polymer degradation.
According to Genesis Biosciences, together, the two components offer operators a simple-to-apply biotech solution that can operate over a wide range of pH values and temperatures and in a range of reactor configurations.
The expansive metabolic capabilities of the Bacillus microorganisms and the universal tolerance of the mineral additive allows application across most organic feed types spanning many industries, including sludge-fed systems, agricultural waste-fed systems, slurry-fed systems, food and municipal-fed systems, landfill leachate systems and one and two-phase configurations.
“With a growing demand on companies and authorities to better their environmental credentials, decrease their waste and lower their carbon dioxide emissions, AD and practices such as sludge to land are now being touted as circular economy champions,” said Dr Chris Charles, senior research scientist and WWT specialist at Genesis Biosciences.
“The ability to take human and other waste streams such as agricultural and food, and turn it into both energy and a fertiliser is attractive from a commercial aspect and a palatable ‘green’ concept that the general public can both understand and appreciate.
“The Evogen WWT Biogas Additive is an innovative product based on a synergistic, dual-phase technology that works to accelerate the biogas conversion rate, decrease the volume of undigested sludge, and increase the yield of biogas production.
“Through this synergy, Evogen Biogas Additive helps to increase the amount of methane produced, decrease the final sludge volume, bolster the stability of the system, and enhance overall productivity.”
According to Genesis, AD is fast becoming an integral part of the wastewater treatment process among local authorities and private companies. The ability to use microorganism to produce methane-rich biogas from sewage sludge and organic waste matter offers the potential to produce heat and electricity from an ever-present and growing waste source.
The company believes although AD has great potential in creating a circular economy, there are still some key challenges and drawbacks, including time, waste, yield, and costs. In terms of time, the process can be slowed down by inhibitory environmental conditions that impact the resident microbial consortia and lead to a decrease in metabolic activity.
Low microbial activity, less than ideal growing conditions, or an inefficient AD system, can also cause losses in methane yields and, therefore, lead to high volumes of residual sludge, which must be processed and disposed of via practices such as landfill or incineration. All these downsides increase the running costs and ultimately impact the cost-effectiveness of AD systems, according to Genesis.
Dr Charles said: “Following the addition of the Evogen Biogas Additive, the biogas conversion rate is accelerated, the volume of undigested sludge is reduced, and the biogas yield is significantly increased, resulting in lower running costs and a greater financial return.
“By partnering interacting Bacillus microorganisms with diverse extracellular enzyme profiles, we can ensure that our additive performs across a broad spectrum of organic substrates from sewage sludge to agricultural and food wastes.
“In combination, both the mineral carrier and the Bacillus microorganisms form a stable product – more so than other sensitive types of microorganisms that could be used as a potential additive – and boast a long shelf-life of up to and over two years.”